1. Field of the Invention
The present invention generally relates to manufacturing methods of magnetic recording media, the magnetic recording media, and magnetic recording and reproducing apparatuses. More specifically, the present invention relates to a manufacturing method of a magnetic recording medium whereby a magnetic pattern is formed by ion doping, the magnetic recording medium, and a magnetic recording and reproducing apparatus.
2. Description of the Related Art
Hard disk drives (HDD) are mainly used as mass storage devices whereby high speed access or high speed transmitting of data can be realized. The surface recording density of the hard disk drives (HDD) is being improved at an annual rate of 100% and further improvement of recording densities is expected.
In order to improve the recording densities of the HDDs, reduction of the track width or the recording bit length is necessary. However, if the track width is reduced, neighboring tracks may easily interfere with each other. Due to such a reduction of the track width, the magnetic recording information may be easily overwritten in the neighboring tracks at the time of recording. Cross-talk due to leakage magnetic fields from the neighboring tracks may easily occur at the time of reproducing.
The above-mentioned issues cause reduction of the S/N ratio of a reproduction signal so that the error rate may be degraded. In addition, if reducing the recording bit length is continued, stability of the bit becomes degraded and the phenomenon of heat fluctuation is generated.
For solving such an issue, a bit patterned type magnetic recording medium has been suggested to reduce influence between neighboring tracks and realize high track densities. See Japanese Examined Patent Application Publication No. 6-28093.
However, in a forming method of the magnetic recording medium by the bit patterned type medium, a portion other than the bit pattern is etched so that the magnetic film is removed and then a non-magnetic material is supplied and flattened to fill in that portion. Hence, it is necessary to perform complex manufacturing processes so that the manufacturing cost may increase.
As a method for solving such an issue, a processing method whereby ions are implanted into a magnetic film so that a magnetic state is partially changed has been suggested. In this method, since the magnetic state is changed by doping with the ions, a complex manufacturing process such as etching, filling or flattening is not required so that increase of the manufacturing cost is prevented.
However, in a related art method for doping with ions, erasure of magnetism in an ion doped area (hereinafter a guard area) cannot be performed sufficiently. Furthermore, in a case where an amorphous magnetic film such as a rare earth transition metal is used as a magnetic film in order to solve this issue, saturation magnetization of a base part (which becomes the recording area) for maintaining the magnetic state is low and therefore it is not proper for high recording densities so that this is not yet utilized.